Test 1 PV test Flashcards
Photovoltaics is a solar energy technology that uses unique properties of semiconductors to directly convert solar radiation into electricity.
true
The majority of the regulations governing electrical system integration are found in the National Electrcial Code.
True
A PWM charge controller pulses the full charge current and varies the width of the pulses to regulate the amount of charge current.
True
A micro-hydroelectric turbine is a device that produces electricity from the flow and pressure of water.
True
Qualifying-facility agreements are intended for small interconnected PV systems.
False
Charging is the process of a cell or battery converting chemical energy to electrical energy and delivering current.
False
Sulfation increases the electrolyte concentration and the available active material, and therefore the capacity of the cell.
False
Supplemental-power PV systems offset a portion of the power needed from the utility, resulting in lower electricity bills.
True
Ground-mounted arrays generally offer less flexibility than building-mounted arrays in the location and orientation of arrays.
False
The voltage between battery terminals is highest at the beginning of a descharge cycle and gradually falls.
True
Equipment grounding is not required for all PV systems.
False
Short-circuit current is associated with zero load resistance and open-circuit voltage is associated with infinite load resistance.
true
overcurrent protection devices are classified by how quickly they acivate.
True
Diesel engines are well suited for constant loads, whereas gasoline engines can respond quickly to changing loads.
True
An n-type semiconductor is a semiconductor that has electron voids.
false
materials, equipment, designs, or installation practices for PV systems are independent of environmental conditions.
False
All current-carrying conductors in the PV output circuit must have disconnect provisions, including the grounded conductor.
True
Energy storage systems are characterized by the form of energy they store and how the energy is utilized or converted into other forms.
True
A disconnect must by manually operable and may be either a switch or a circuit breaker.
True
Most residential and commercial loads are DC loads.
False
Lead-acid batteries are the most common type of batteries used in PV systems.
True
Spanning is used with lag screws.
False
Numerous not-for-profit organizations work to promote and further the PV industry, including organizations involved in research, marketing, installer training, and standards development.
True
A flat-plate collector can utilize any solar radiation, direct or reflected, that strikes its surface.
True
Since rack mounts use an open, trusslike structure, air can circulate freely around the modules and keep them cool.
True
A distributed-generation system may serve as the only source of power for a consumer, or as back-up or supplemental power for a utility grid connection.
True
A blocking diode is a diode used to pass current around, rather than through, a group of PV cells or modules.
False
All Utility-interactive inverters must be able to detect power outages and discontinue transfer of power until the utility system returns to normal operation.
True
Most utility electrical power is produced by rotating generators that are mechanically driven.
True
Interactive inverters act like a voltage source, while generators act like a current cource.
False
A diversionary charge controller is a charge controller that regulates charging current to a battery system by diverting excess power to an auxiliary load.
true
PV power plants can be located closer to populated areas than can conventional power plants because they do not involve hazardous materials or cause air, water, or noise pollution.
True
The photographic method of shading analysis compares a panoramic photo of the potential obstructions to a sun path diagram.
True
Liability insurance is required by most utilities that have interconnection standards.
True
Modules mounted directly on the roof surface increase the heat transfer into a building.
True
Lead-calcium batteries experience less gassing and lower self-discharge rates than lead-antimony batteries.
True
Air mass depends upon the time of day, the time of year, and the altitude and latitude of the specified location.
True
Breakdown voltage is the minimum reverse-bias voltage that results in a rapid increase in current through an electronic device.
True
Shading on solar thermal collectors reduces performance by an amount proportional to the level of shading.
True
The two major types of radiation reaching the ground are direct radiation and diffuse radiation.
True
Direct radiation is radiation that is scattered by the atmosphere and clouds.
False
Short circuit voltage is the maximum voltage on an I-V curve.
False
Some amount of series resistance in a PV system is unavoidable because all conductors and connectors have some resistance.
True
Three-phase inverter output can be achieved by using three smaller inverters and connecting each inverter to a different phase.
True
The array azimuth angle is the vertical angle between horizontal and the array surface
False
A photoelectrochemical cell uses semiconductors to produce electricity from light.
False
Solar radiation is a highly variable resource and significant differences exist among regions in the United States.
True
Multistage charge controllers with an absorption charge cycle will also include a float charge setpoint, which is a slightly lower voltage than the voltage regulation setpoint.
True
A secondary battery is a battery that can store and deliver electrical energy but cannot be recharged.
False
A hybrid system is a PV system that can operate in either utility-interactive or stand-alone mode, and uses battery storage.
False
In the United States, the technical requirements for PV systems are established through national codes and standards publish by _____.
Institute of Electrical and Electronics Engineers (IEEE), Underwriters Laboratories (UL), and the National Fire Protection Association (NFPA).
Solar radiation is _____ by components of the atmosphere, including ozone, carbon dioxide, and water vapor, as well as other gases and particles.
absorbed, scattered, and reflected
A _____ is a rod, plate, or structure that establishes a connection with the earth.
grounding electrode
A _____ battery is a battery that uses a combination of plate designs to maximize the desirable characteristics.
hybrid
A(n) _____ is a visit to the installation site to assess the site conditions and establish the needs and requirements for the system.
site survey
Portable PV systems power mobile loads such as ______.
vehicles, temporary signs, lighting, and handheld devices.
A(n) ______ turbine is a device that compresses and burns a fuel-air mixture, which expands and spins a turbine.
gas
_____ is the point in the sky directly overhead a particular location.
Zenith
A(n) _____ is a company that produces and/or distributes electricity from its central generation point to the consumer.
utility
_____ is the current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
Ampacity
A(n) _____ is Earth’s orbital position when solar declination is at its minimum or maximum.
solstice
_____ is the amount of time a fully charged battery system can supply power to system loads without further charging.
Autonomy
A(n) _____ mount is an array mounting system that automatically orients the array to the position of the sun.
sun-tracking
_____ energy is expected to compose an increasingly larger portion of energy production.
Renewable
_____ is the angle between the direction a compass needle points (towards magnetic north) and true geographic north.
Magnetic declination
The service conductors in a supply-side connection must be sized for at least ____% of the continuous load current, based on the PV system inverter maximum current output rating.
125
A battery _____ is a group of batteries connected together with series and parallel connections to provide a specific voltage and capacity.
bank
A _____ load is a dynamic structural load due to periodic motion.
vibration
Positioning windows to face _____ allows maximum sunlight and heat into the building.
south
A(n) _____ is a collection of cells that are contained in the same case and connected together electrically to produce a desired voltage.
battery
_____ is the ratio of the increase in battery charge to the amount of charge supplied to the battery.
Charge acceptance
Distributed-generation systems can include _____.
PV systems, wind turbines, and engine generators
_____ circuit breakers are circuit breakers on the load side of the main service disconnect that supple PV power to the busbar.
Back-feed
A PV system that operates in parallel with and is connected to the electric utility grid is called a(n) _____ PV system.
utility-interactive, grid-connected, and interactive
A _____ cell is an electrochemical device that uses hydrogen and oxygen to produce DC electricity, with water and heat as byproducts.
fuel
A(n) _____ is a collection of information about a facility’s or customer’s energy use.
energy audit
The _____ is the percentage of energy remaining in a battery compared to the fully charged capacity.
state of charge
_____ store energy in an electrical field developed by two oppositely charged parallel conductive plates separated by a dielectric (insulating) material.
Capacitors
A(n) ____ switch allows an electrical system to be switched from a primary power source to an alternate power source in order to keep critical loads operating.
transfer
A(n) _____ is a device that converts DC power into AC power.
inverter
